This invention relates to a method for coating of powders with nylon and, more particularly, to the production of agglomerates of individual coated particles. This invention further relates to compressing of the coated particles and/or coated powder to form a shaped structure, such as, a molded article.
Various methods of coating finely divided particles of metals or other materials are known and used in the art. These methods lead to products which are advantageous for one or more reasons over the use of the raw materials.
For instance, in the paint and ink manufacturing industries, vast amounts of organic and inorganic pigments are used. These pigments are obtained in finely divided form, the particles often having sizes in the sub-micron range. The pigments, therefore, are extremely bulky and take up large amounts of space. Furthermore, due to their extremely light, fluffy nature, when compounding them into the ink or paint, wetting problems are experienced leading to the need for wetting agents and other additives. Furthermore, during compounding the pigments tend to be dispersed into the air and they create a great contamination problem both within the manufacturing facility and outside of the same. One of the successful methods for combating these problems is the conversion of the pigments into so-called "color concentrates" wherein the pigment is milled into nylon or some other carrier on a roll mill. Of course, during this milling operation, the same handling problems are experienced.
In other industries, such as the manufacture of magnetic articles, it is also necessary to intimately mix finely divided particles of a magnetic material with a resinous substance. Merely mixing the two dry materials is not satisfactory due to the small particle size. One method which has been used is to mix the finely divided metal particles in a molten resin and, after cooling and solidifying the mixture, pulverizing the mass. This is a difficult and expensive process.
A method of producing nylon coated powders which could be used efficiently in forming shaped structures on a commercial scale and which would be free of the aforementioned disadvantages is therefore highly desired.